JP4412721B2 - Control method in wireless communication system - Google Patents

Description

The present invention relates to a control method in a wireless communication system in which a plurality of wireless terminals communicate via a base station .

  In recent years, with the improvement in performance of devices, there are an increasing number of cases in which specific applications that use communication of the same specification in different devices are mounted. As an example, a digital camera and a printer are connected and printing is performed directly from the digital camera. Conventionally, in such a case, a digital camera and a printer are connected by wire. Wireless communication is desired due to the troublesomeness of this wired connection (see, for example, Patent Document 1). However, when wirelessly connected, there is a problem that connection with a desired partner is not compensated.

As a solution to this problem, for example, it is necessary to connect to the partner once and inquire about the device capability of the partner.
Japanese Patent Laid-Open No. 11-275501

  However, if the connection up to the application level is performed in order to guarantee the connection with the desired party, the following problem occurs particularly when there is no device having a corresponding application.

  Since there is no device that responds to a response request from here, there is a problem that the trigger for switching the wireless network is a timeout process, which takes time.

  In addition, when time is required, in the case of a device that is driven by a normal battery such as a digital camera, the power for the waiting time is consumed, so that the capacity of the battery that the user can normally use is reduced. It will be.

The present invention can detect a wireless network having an environment for executing a direct printing application for performing direct printing between a printing apparatus and an imaging apparatus from surrounding wireless networks before connecting to the wireless network. The purpose is to do.

The present invention is a control method in a wireless communication system in which a plurality of wireless terminals communicate via a base station, and a base station corresponding to a direct printing application that performs direct printing between an imaging device and a printing device A reception step of receiving a registration request as a wireless terminal compatible with the direct printing application from a wireless terminal participating in a wireless network formed by a base station, and according to reception of the registration request in the reception step The information signal indicating that the base station supports the direct printing application and the device type of the wireless terminal that transmitted the registration request are transmitted in the notification signal for synchronizing the wireless network. Each wireless terminal can support the direct printing application based on the notification signal received from the base station. A detecting step of detecting a first wireless network formed by a wireless base station and a wireless terminal of a device type that is a communication partner of the terminal when the direct printing application is executed, If the first wireless network can be detected in the detecting step, an execution step of connecting to the first wireless network and executing the direct printing application with the wireless terminal of the device type serving as the communication partner; if unable to detect the first wireless network in the detection step, characterized by chromatic and searching step of searching for the broadcast signal transmitted from another base station.

According to the present invention, a wireless network in an environment suitable for directly executing a printing application, that is, a base station capable of supporting a direct printing application is formed from wireless networks formed by surrounding base stations. In addition, it is possible to detect a wireless network in which a wireless terminal of a device type that is a communication partner of the local terminal participates when executing the direct printing application before connecting to the wireless network. For example, even if a wireless terminal of a device type that is a communication partner is participating, if the base station does not directly support the printing application, it is not used because it is not connected to the wireless network formed by the base station. Wireless network connection and wireless network switching can be prevented, and unnecessary power consumption can be suppressed .

  The best mode for carrying out the invention will be described below in detail with reference to the drawings. In this embodiment, a direct printing system (DPS) that performs a printing process or a recording process by logically connecting a printer, a digital camera, a digital video, and a storage device without going through a computer as a specific application will be described as an example. To do. As a wireless communication method, a case where the well-known IEEE 802.11 is used will be described.

  As Example 1, first, in the infrastructure mode defined by IEEE802.11, information indicating that the access point (AP) periodically transmits a beacon is an AP with a DPS support function and information on a DSP-compatible device. The process of confirming whether a DSP-compatible communication partner exists on the wireless network before the DSP device establishes a link at the DSP level will be described.

  FIG. 1 is a diagram illustrating a configuration of a wireless network according to the first embodiment. As shown in FIG. 1, an infrastructure mode wireless network has an access point (AP) 101 in a wireless LAN compliant with IEEE802.11 and a wireless communication function compliant with IEEE802.11, and communicates with the AP 101 wirelessly. The digital camera 102a, 102b, the printer 103, the computer 104, a wired network 105 to which the AP 101 is connected, and a computer 106 connected to the wired network 105 are configured.

  FIG. 2 is a diagram showing a basic format of a MAC frame that conforms to IEEE 802.11. As shown in FIG. 2, the MAC frame includes a frame control field 201, a duration / ID field 202, address fields 203, 204, 205, and 207, a sequence control field 206, a frame body field 208, and an FCS field 209. It consists of and.

  FIG. 3 is a diagram showing a format of a management frame that is one type of MAC frame. As shown in FIG. 3, the management frame includes a frame control field 301, a duration / ID field 302, a destination address field 303, a source address field 304, a BSSID field 305, a sequence control field 306, a frame body. The field 307 and the FCS field 308 are configured. The frame body 307 includes an element ID 310 indicating the element type, a length 311, and an element body 312.

  FIG. 4 is a diagram showing attribute information of each frame stored in the frame body of the beacon frame. The beacon frame is a case where “1000” is described in the subtype (bit positions 7 to 4) of the frame control field in the management frame, and is transmitted periodically by the AP 101 to notify the presence of the wireless cell. It is a frame. Further, in the ad hoc mode, one or all of a plurality of terminals constituting an IBSS (Independent Basic Service Set) transmit. The ad hoc mode will be further described later.

  As shown in FIG. 4, the frame body of the beacon frame is composed of attribute information called a plurality of elements. In the example shown in FIG. 4, only representative attribute information is shown.

  FIG. 5 is a diagram illustrating attribute information of each frame stored in the frame body of the beacon frame according to the first embodiment. As shown in FIG. 5, in order to support a specific application, an element ID 20 indicating that the AP has a DPS support function is added to the frame body of the beacon frame and transmitted.

  Also, an element ID 21 indicating the number of DPS devices registered in the AP 101 is added and transmitted. In the example shown in FIG. 5, three printers and two digital still cameras (DSC) are registered as the number of DPS devices.

  Here, a terminal device such as a digital camera or printer having the DPS capability receives a beacon periodically transmitted by the AP 101, and if it is found that the element in the beacon is the AP 101 with the DPS support function, After the wireless LAN connection process, the AP 101 is informed of the fact that it is DPS compatible and the type of device such as a printer or digital camera. This notification is realized by transmitting to the AP 101 using a normal data frame.

  As a result, the AP 101 periodically requests a response from the DPS device registered in the AP 101, and if there is no response, the AP 101 is assumed to have left the wireless network, and the number of managed DPS devices is reduced. A beacon that reflects the situation can be transmitted.

  Further, when the digital camera wants to connect to the printing device using DPS, the received beacon is checked to check whether the printing device exists in the AP 101 with the DPS support function. As a result, if a printing device exists and the digital camera has already joined the wireless network, a link between the printing device and the application level, that is, the DPS is established.

  If a printing device is present and the digital camera is not participating in the wireless network of the corresponding AP 101, after the wireless connection to the AP 101, its own attribute information is notified to the AP 101, and then the printing device and the application level That is, a DPS link is established.

  Further, when there is no printing device, the beacon of another AP with DPS support function is checked, and the printing device joins the wireless network of the registered AP or notifies the user that printing cannot be performed. .

  Here, a process for confirming the existence of a DPS-compatible device on the wireless LAN by using a beacon periodically transmitted from the AP 101 with the DPS support function in the first embodiment will be described with reference to FIG. Here, the DPS compatible devices are only the digital cameras 102a and 102b and the printer 103, and the case where the digital camera 102b is disconnected from the wireless network after registration will be described as an example.

  Note that the procedure for establishing the link of the wireless network between the AP 101 and the wireless terminals 102 to 104 is performed in a known sequence defined by IEEE802.11, and details thereof are omitted. In addition, it is assumed that an ESS (Extended Service Set) ID, which is a channel used for establishing a wireless link and a network identification ID, is appropriately set.

  FIG. 6 is a diagram illustrating a sequence for confirming the presence of a DPS-compatible device on the wireless LAN using a beacon according to the first embodiment.

  First, when there is no DPS-compatible device on the wireless LAN (601), the beacon has an element indicating that the AP 101 has a DPS support function (element ID 20 shown in FIG. 5) and zero printers being registered. And an element indicating that the digital camera being registered is 0 (element ID 21 shown in FIG. 5).

  The printer 102 that is found to be an AP with a DPS support function by this beacon transmits a DPS registration request from the printer 102 to the AP 101 after wireless connection with the AP 101 (602). When the AP 101 receives the DPS registration request, the AP 101 changes the beacon parameters to be transmitted to one newly registered printer and 0 to the registered digital camera (603).

  Also, the digital camera 102a, which is known to be an AP with a DPS support function from this beacon, transmits a DPS registration request from the digital camera 102a to the AP 101 after wireless connection with the AP 101 (604). When the AP 101 accepts the DPS registration request, the AP 101 changes the beacon parameters to be transmitted to one printer that is already registered and one digital camera that is newly registered (605).

  Similarly, when the digital camera 102b transmits a registration request (606), the AP 101 changes the beacon parameter to be transmitted to one printer that is being registered and two digital cameras that are newly registered.

  In addition, in the wireless LAN of the IEEE 802.11 standard, participation in the wireless network is managed, but withdrawal is not managed. Therefore, if the user does not confirm the withdrawal by any method, there is a discrepancy between the device that is actually participating in the wireless network and operating and the device information that is notified in the beacon.

  Therefore, the AP with the DPS support function periodically requests a response to all the devices that have requested registration (609, 611, 6013). The device that has returned a response to this response request is treated as if it is still participating in the wireless network (610, 612), and has left the wireless network if there is no response within a certain time after sending the response request. Treat as a thing (614). In the example illustrated in FIG. 6, the digital camera 102b does not return a response to the response request. As a result, in the beacon to be transmitted next (615), the parameter is changed to one printer and one digital camera.

  As a result, the digital camera 102a that has completed registration with the AP 101 refers to the type and number of DPS-compatible devices in the beacon periodically transmitted by the AP 101, so that one printer that supports DPS is located in the same wireless network as the digital camera 102a. You can see that it exists. When the user of the digital camera 102a selects direct printing processing, a link is established between the printer 103 and the DPS application layer, and after the link is established, DPS capability information is exchanged between the printer 103 and the digital camera 102a. . After this capability information exchange, the digital camera 102a transmits print information obtained by processing a photograph under printing conditions supported by each other to the printer 103 to perform printing.

  According to the first embodiment, the DSP device adds the information indicating the DPS support function AP and the information related to the DSP compatible device to the beacon periodically transmitted by the access point (AP), so that the DSP device can control the DSP. Before performing link establishment at the level, it is possible to confirm whether or not there is a DSP compatible communication partner on the wireless network.

  Next, Embodiment 2 according to the present invention will be described in detail with reference to the drawings. The second embodiment relates to the operation in the ad hoc mode defined by IEEE802.11. In particular, when one terminal among a plurality of terminals in the ad hoc mode transmits a beacon periodically, the terminal that transmits the beacon changes. A case will be described.

  FIG. 7 is a diagram illustrating a configuration of a wireless network according to the second embodiment. As shown in FIG. 7, the ad hoc mode wireless network includes a digital camera 701, a printer 702, and a scanner 703 having a wireless communication function compliant with IEEE802.11.

  Here, the process of confirming the presence of a DPS-compatible device on the wireless LAN using a beacon will be described with reference to FIG. The basic operation of the wireless terminal that transmits a beacon is the same as that of the AP in the infrastructure mode, and the collected DPS correspondence information is reflected in the corresponding element of the beacon shown in FIG. If the wireless terminal that transmits a beacon changes midway, the information that manages the DPS-compatible device is passed from the wireless terminal that previously transmitted the beacon to the wireless terminal that newly transmits the beacon. Thus, it is possible to continuously transmit DPS device information on a beacon without newly collecting device information.

  FIG. 8 is a diagram illustrating a sequence for confirming the presence of a DPS-compatible device on the wireless LAN using a beacon according to the second embodiment. Here, a case where the printer 701 transmits a beacon will be described.

  First, when there is no DPS-compatible device on the wireless LAN (801), the beacon has an element indicating that it is a terminal with a DPS support function and the printer 701 itself, as in the first embodiment, and registration is completed. Therefore, an element indicating that one printer is registered and zero digital cameras are registered is included.

  The digital camera 702a, which is found to have a terminal with a DPS support function from this beacon, transmits a DPS registration request from the digital camera 702a to the printer 701 after wireless connection with the printer 701 (802). When the printer 701 receives the DPS registration request, the printer 701 changes the beacon parameters to be transmitted to one printer that is being registered and one digital camera that is newly registered (803).

  Also, the digital camera 702b, which is known to be a terminal with a DPS support function from this beacon, transmits a DPS registration request from the digital camera 702b to the printer 701 after wireless connection with the printer 701 (804). When the printer 701 accepts the DPS registration request, the printer 701 changes the beacon parameter to be transmitted to one printer that is being registered and two digital cameras that are newly registered (805).

  In addition, in the wireless LAN of the IEEE 802.11 standard, participation in the wireless network is managed, but withdrawal is not managed. Therefore, if the user does not confirm the withdrawal by any method, there is a discrepancy between the device that is actually participating in the wireless network and operating and the device information that is notified in the beacon.

  Therefore, the terminal with the DPS support function periodically requests a response from all the devices that have requested registration (806, 808). The device that has returned a response to this response request is treated as if it is still participating in the wireless network (807). If there is no response within a certain time after sending the response request, it is assumed that the device has left the wireless network. Handle (809). In the example illustrated in FIG. 8, the digital camera 702b does not return a response to the response request. As a result, in the beacon to be transmitted next (810), the number of printers whose parameters are being registered is changed to one and the number of digital cameras is changed to one.

  Next, an operation when a terminal that transmits a beacon is changed while a terminal on the wireless network is operating will be described. In the wireless network, it is assumed that there is one printer compatible with DPS and two digital cameras.

  The sequence after 811 shown in FIG. 8 is processing when the terminal that transmits the beacon is changed. First, when the digital camera 702a transmits a beacon (811), since there is no DPS device information other than itself in this state, the managed printer is 0 and the digital camera is 1 Is described in the element. At this time, the printer 701 that has transmitted the beacon until then transmits the DPS management table created by itself to the digital camera 702a that is a new beacon sender (812). Based on the result, the digital camera 702a can transmit from the next beacon as one managed printer and two digital cameras.

  According to the second embodiment, in the wireless network in the ad hoc mode, when one terminal among a plurality of terminals periodically transmits a beacon, or when the terminal that transmits the beacon changes, the DSP device Before establishing a link at the DSP level, it is possible to confirm whether or not there is a DSP compatible communication partner on the wireless network.

  Next, Embodiment 3 according to the present invention will be described in detail with reference to the drawings. In the third embodiment, the operation in the ad hoc mode defined by IEEE802.11 will be described, particularly in the case where all the terminals in the ad hoc mode transmit beacons.

  The configuration of the wireless network in the third embodiment is the same as that of the second embodiment described with reference to FIG.

  Here, the process of confirming the presence of a DPS-compatible device on the wireless LAN using a beacon will be described with reference to FIG. The terminal in the ad hoc mode transmits a beacon frame periodically transmitted by itself by adding an element indicating its own device type information with a DPS support function. In addition, if the other ad hoc mode terminal also has a DPS function, it also has a DPS support function, adds an element indicating its own device type information, and transmits a beacon. A DPS function management table in which terminals and DPS functions are associated with each other is created.

  FIG. 9 is a diagram illustrating a sequence for confirming the presence of a DPS-compatible device on the wireless LAN using a beacon according to the third embodiment. Since each terminal has its own information as an initial value, the management table of each terminal has one printer for printer 701, zero cameras (911), zero printer for digital camera 702a, and one camera ( 821), the digital camera 702b has 0 printers and 1 camera (931).

  Here, when the printer 701 first transmits a beacon (901), by receiving this beacon, the management table of each terminal is such that the printer 701 has one printer, the camera 0 (912), and the digital camera 702a has a printer 1. In the digital camera 702b, one printer and one camera (932) are provided. The printer 701 does not change because there is only its own information at this point.

  Next, when the digital camera 702a transmits a beacon (902), by receiving this beacon, the management table of each terminal has one printer for the printer 701, one camera (913), and a printer for the digital camera 702a. One printer, one camera (923), and one digital camera 702b are one printer and two cameras (933). Here, the reason that only the digital camera 702b is the two cameras is that the presence of a camera other than itself is detected by receiving the beacon of the digital camera 702a.

  Next, when the digital camera 702b transmits a beacon (903), the management table of each terminal is received by receiving the beacon. The printer 701 has one printer, two cameras (914), and the digital camera 702a has a printer. One printer, two cameras (924), and one digital camera 702b are one printer and two cameras (934).

  Next, since the beacon of a terminal out of a communicable range or a terminal whose power is turned off cannot be received, a process for deleting information related to a terminal that no longer receives a beacon from the DPS function management table will be described. In addition, each terminal shall record the time information which received the beacon last time in the management table.

  As shown in FIG. 9, a case will be described as an example where the digital camera 702b no longer exists in the wireless network when the printer 701 transmits a beacon (904).

  The management tables (915, 925) of the printer 701 and the digital camera 702a do not change at this stage. Next, the digital camera 702a transmits a beacon (905). Even at this stage, the management tables (916, 926) of the printer 701 and the digital camera 702a do not change.

  Here, with reference to the beacon reception information recorded in the management table, if the beacon cannot be received before the specified time elapses, the terminal is treated as having left the wireless network. Since the digital camera 702b has left the wireless network, no beacon is sent.

  The printer 701 and the digital camera 702a cannot receive the beacon even after waiting for a predetermined time after the digital camera 702b transmits the beacon last time (906), so the digital camera 702b is deleted from the management table, and the printer 701 and the digital camera 702a. In both cases, the management tables (917, 927) are one printer and one camera.

  The digital camera 702a that created the DPS function management table by the above sequence refers to the DPS function management table as needed. When the user of the digital camera 702a selects print processing, the digital camera 702a refers to the DPS function management table and selects a printer. If the printer 701 is selected, a link in the DPS application layer is established with the printer 701. After the link is established, the DPS capability information between the printer 701 and the digital camera 702a is exchanged. After exchanging the capability information, the digital camera 702a transmits print information obtained by processing a photograph under printing conditions supported by each other to the printer 701 to perform printing.

  According to the third embodiment, even in a case where all terminals periodically transmit beacons in an ad hoc mode wireless network, DSP compatible communication is performed on the wireless network before the DSP device establishes a link at the DSP level. It can be confirmed whether or not the other party exists.

  Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copier, a facsimile machine, etc.) composed of a single device. It may be applied.

  Another object of the present invention is to supply a recording medium in which a program code of software realizing the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the recording medium in the recording medium. Needless to say, this can also be achieved by reading and executing the programmed program code.

  In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code constitutes the present invention.

  As a recording medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used. be able to.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

1 is a diagram illustrating a configuration of a wireless network in Embodiment 1. FIG. It is a figure which shows the basic format of the MAC frame of a standard by IEEE802.11. It is a figure which shows the format of the management frame which is one type of MAC frame. It is a figure which shows the attribute information of each flame | frame stored in the frame body of a beacon frame. It is a figure which shows the attribute information of each flame | frame stored in the frame body of the beacon frame in Example 1. FIG. It is a figure which shows the sequence which confirms presence of the DPS corresponding | compatible apparatus on wireless LAN by the beacon in Example 1. FIG. 6 is a diagram illustrating a configuration of a wireless network in Embodiment 2. FIG. It is a figure which shows the sequence which confirms presence of the DPS corresponding | compatible apparatus on wireless LAN by the beacon in Example 2. FIG. It is a figure which shows the sequence which confirms presence of the DPS corresponding | compatible apparatus on wireless LAN by the beacon in Example 3. FIG.

Explanation of symbols

101 Access point (AP)
102 Digital Camera 103 Printer 104 Computer 105 Wired Network 106 Computer

Claims (5)

A control method in a wireless communication system in which a plurality of wireless terminals communicate via a base station,
Base stations that support direct printing applications that perform direct printing between the imaging device and the printing device
A receiving step of receiving a registration request as a wireless terminal capable of supporting the direct printing application from a wireless terminal participating in a wireless network formed by the base station;
In response to the reception of the registration request in the reception step, the information indicating that the base station supports the direct printing application and the registration request are transmitted as a notification signal for synchronizing the wireless network. A transmission step of transmitting including the device type of the wireless terminal,
Each wireless terminal
Based on the notification signal received from the base station, a base station that is compatible with the direct print application is formed, and a wireless device of a device type that is a communication partner of its own terminal when executing the direct print application A detecting step of detecting a first wireless network in which the terminal is participating;
An execution step of connecting to the first wireless network and executing the direct printing application with a wireless terminal of a device type serving as a communication partner when the first wireless network can be detected in the detection step; ,
If the first wireless network cannot be detected in the detection step, a search step for searching for the notification signal transmitted from another base station;
Control method in a wireless communication system characterized by having a. 2. The control method in a wireless communication system according to claim 1, wherein, in the transmission step, the number of wireless terminals that have transmitted the registration request for each device type is also included in the notification signal. The base station
A request step for periodically requesting a response to the wireless terminal that has transmitted the registration request;
An update process for updating information included in the notification signal according to whether there is a response to the request;
The control method in the radio | wireless communications system of Claim 1 or 2 characterized by the above-mentioned. The base station
Before receiving the registration request in the reception step, only the information indicating that the base station supports the direct printing application is included in the notification signal and transmitted.
The wireless terminal that transmits the registration request is:
In response to receiving the notification signal including only information indicating that the base station supports the direct printing application, the base station is connected to a wireless network formed by the base station and transmits the registration request. The control method in the radio | wireless communications system of any one of Claim 1 thru | or 3 characterized by the above-mentioned. Each wireless terminal is
A search step of notifying the user that the direct print application cannot be executed if the first wireless network cannot be detected even after searching for the notification signal transmitted from another base station in the search step; The control method in the radio | wireless communications system of any one of Claim 1 thru | or 4 characterized by these.

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